On Modulation, Coding and Signal Processing for Optical and Magnetic Recording Systems

Volker Braun

Digital Communications Group,
Institute for Experimental Mathematics,
University of Essen,
Essen, Germany

February 24, 1997
Supervisor: Prof. Dr.-Ing. A.J. Han Vinck
Advisor: Dr. K.A. Schouhamer Immink,
Philips Research Laboratories, Eindhoven, The Netherlands

Ph.D. Committee:
Prof. Dr.-Ing. A.J. Han Vinck,
Prof. Dr.-Ing. R. Tracht, University of Essen, Essen, Germany,
Prof. Dr.-Ing. S.B. Luitjens, University of Twente, Enschede, The Netherlands

Keywords: Magnetic recording, optical recording, modulation codes, constrained codes, DC-free codes, runlength-limited codes, Golay sequences, channel characterization, nonlinear distortion, Volterra model.

Abstract: Different problems of modulation, coding and signal processing for optical and magnetic recording systems are considered. We investigate relevant statistical properties of combined DC-free runlength-limited (DCRLL) modulation codes. Such codes are widely applied in optical recording systems, for example, in the CD player. In particular, we focus on the basic trade-offs between the rate of DCRLL codes and the amount of suppression of low-frequency components. Further, we analyze advanced detection algorithms for use in the DCC system, where a DC-free modulation code is applied. Appropriate detection algorithms are developed and their error rate performances are evaluated using computer simulations and experimental data. Finally, we consider the application of Golay complementary sequences for measuring the transfer characteristics of the magnetic recording channel. Our experimental channel suffers from nonlinear distortion introduced by a magnetoresistive sensor. Using a nonlinear Volterra channel model, we derive an improved technique which allows to measure the channel response without artefacts caused by even order nonlinear distortion.

Please reply to:

Volker Braun
Institute for Experimental Mathematics Ellernstr.
29 45326 Essen Germany
Phone: +49 201 3206448
Fax: +49 201 3206463
E-mail: volker@exp-math.uni-essen.de
Web site: http://www.exp-math.uni-essen.de